Laser diodes (LDs) have the advantage of excellent linearity of light. However, when a laser diode is used in a vehicle headlamp or the like where a wide distribution of emitted light is desired, such linearity of light is a disadvantage. An additive capable of controlling light scattering or the like has been applied to induce the spreading of light, but such an additive may cause a problem such as a decrease in light transmittance, backscattering that reduces luminance, or the like.